Carbon paper



Feb" 7, 11950 c, COOK, JR 2,496,856

I OMRLES B. Coon JR.

HTTORNEY.

Patented Feb. 7, 1950 UNITED STATES PATENT OFFICE CARBON PAPER Charles B. Cook, Jr., West Hartford, Conn.

Application June 12, 1946, Serial No. 676,251

2 Claims.

This invention relates to carbon paper and more particularly to a construction for a carbon paper sheet which will prevent curling of the paper.

It is well known that carbon paper sheets have a strong tendency to curl and thereby render it diflicult to handle such sheets and to separate them from each other.

An object of my invention, therefore, is to provide sheet material for carbon paper which is so formed that it will be stifiened against curling; particularly at the corners of the sheet.

A further object of the invention is to form the sheet so as to stiffen it longitudinally as well as laterally in order to prevent curling in either direction,

Further objects and advantages of the invention will be more clearly understood from the following description and from the accompanying drawing, in which-- Fig. 1 is an elevational plan view of a carbon paper sheet constructed in accordance with my invention.

Fig. 2 is a fragmental view, in elevation, of a portion thereof on a greatly magnified scale.

Fig. 3 is a sectional end view of a portion of the sheet on line 33 of Fig. 2.

Fig. 4 is a similar view on a further magnified scale and showing a modification in the construction of the sheet.

Fig. 5 is an elev-ational plan view of a further modified form of the sheet.

Fig. 6 is a magnified sectional edge view of a portion of the sheet on line 66 of Fig. 5.

Fig. 7 is an enlarged fragmental view, in elevation, of a further modified form of my invention.

Fig. 8 is a sectional end view thereof.

As illustrated in the drawings, the numeral 5 denotes a sheet of carbon paper which may be of ordinary thickness and texture with a coating of carbon applied to one side thereof.

My invention provides for forming said sheet with corrugations comprising parallel ribs running preferably laterally on the sheet, as clearly shown in Figs. 1 to 4. The said ribs may be very narrow and preferably running at approximately 25 to 40 per inch, but the size of the said ribs may be varied as desired.

It has been found that these ribs will materially stiffen the sheet laterally, so that the curling of the edges of the corners thereof is thereby resisted and the sheet will lie preferably flat.

It is preferred that the grain of the paper, which is illustrated in broken lines in Figs. 2 and 4, should run lengthwise to the sheet and that the ribs 6 should run crosswise to said grain. This will render the sheet resistant to curling in either direction since it will be normally stiffened in the longitudinal direction by the run of the fibers in the sheet and in the lateral direction by the ribs 6.

In the modified form shown in Figs. 5 and 6, the sheet may be so formed as to have the parallel stiffening ribs extending in both directions thereon and thereby stiffen the sheet against curling in either direction. In this embodiment of my invention, the said ribs are formed upon the sheet in a particular design wherein each parallel ribbed portion is intersected with another ribbed portion with ribs running crosswise thereto so that the sheet is stifiened by said ribs against curling in any portion and in either direction.

In the modified form shown in Fig. '7, the sheet is stiffened by means of a pattern of embossments 8 which, as shown, is of diamond shape but may be of any other form desired.

It will be noted that the corrugations, as well as the embossments, are so formed, that upon being struck by the type of a typewriter, the sheet will immediately flatten and thus provide a full and unbroken impression. This is permitted by the sidewalls of the corrugations or embossments being substantially at an angle to the surface of the carbon sheet, rather than perpendicular thereto, so that upon being struck by the type they will immediately flatten against the surface of the sheet which is being typed and therefore permit a, full impression of the type.

Other patterns of ribs or embossments than those shown may be used in attaining the objects hereinabove set out and they may be formed in any manner well known to those skilled in the art.

I claim:

1. For carbon paper, a sheet corrugated to provide a plurality of parallel closely juxtaposed fine stiffening ribs extending to at least one edge thereof and running crosswise to the direction of the grain of said sheet.

2. Carbon paper as defined in claim 1, wherein the parallel closely juxtaposed fine stiffening ribs are in the range of approximately 25 to 40 to the inch.

CHARLES B. COOK, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,836,907 Dienelt Dec. 15, 1931 2,173,972 Lane Sept. 26, 1939 

